You seem to have figured out the whole system to meet your needs.

That Electrodyne unit looks like it will last forever.

I have had some first-hand knowledge and much more second and third hand knowledge of the Fischer Panda gensets. Like a fine piece of clockwork, they are a beauty to look at. As Tom Keffer say, the design goal of compactness was well met. That said, mechanics run the other way at the mere mention of the brand. They are a nightmare to work on. Simple things like changing the oil are not.... simple.

I hope to learn more about Polar Power gensets. Anyone here have experience with them?

We have about 1,100 hours on our Yanmar, so have a lot of life left on it. I don't mind squandering some of it on charging batteries if the acceptance rate is high and engine run time is short. Nigel Calder does calculate that the amortized cost of running a main engine is about $4/hr, not counting fuel and routine maintenance costs. That's based on a 5,000 life and $20k replacement cost. Those are real world estimates assuming that a yard does the installation and that the engine is treated like a typical sailboat auxiliary.

Even though an Electrodyne is enticing, there are a couple reasons I'll probably go with Balmar. The AltMount.com adapters are designed to fit a Balmar 95-210 without modification. Also, Balmar is close to Seattle. Some comfort when here, but perhaps not when off cruising.